William O Brien State Park

Marine On Saint Croix, Minnesota · Campsite openings, cancellations & sold-out date alerts

State ParksSmall parkWatched around the clock

Weekend availability

Live from Minnesota State Parks · checked Sep 19, 1:25 PM PT

Sold out 1 of the next 5 weekends — exactly when cancellation alerts earn their keep.

  • Fri, Sep 25
    Sold out
  • Fri, Oct 2
    Limited
    3/6 campgrounds
  • Fri, Oct 9
    Limited
    2/6 campgrounds
  • Fri, Oct 16
    Limited
    1/6 campgrounds
  • Fri, Oct 23
    Limited
    2/6 campgrounds
Alert me when a sold-out weekend opens

Sold out for your dates? We'll tell you the second a site opens.

Cancellations at William O Brien State Park get rebooked in minutes. We check Minnesota State Parks around the clock and alert you before the crowd refreshes the page.

Set an alert for Marine On Saint Croix$9.99/mo — why we charge

Not ready to subscribe? Get a free weekend heads-up.

We'll email you if William O Brien State Park opens up for a weekend you pick. No account needed.

How booked is William O Brien State Park?

as of July 23

Weekends book out well ahead here — 1 of the 3 Saturdays we sampled, as far out as Jan 2027, are already sold out. When a site frees up it's gone again within minutes, so people watch William O Brien State Park and hear the instant one opens for their dates. Weekdays still have room — for now.

Weekends (Saturday night)

Aug 8Open
Oct 24Open
Jan 9Sold out

Weekdays (Wednesday night)

Aug 19Open
Nov 4Open

Availability checked directly against the reservation system, out to 6 months ahead.

Park type

State Parks

Small park

Online booking

Available on Minnesota State Parks

Official state reservation system

Alert coverage

Checked around the clock

Openings, cancellations & new dates

Where William O Brien State Park is

16821 O'Brien Trail North

Marine On Saint Croix, MN 55047

45.2254, -92.7636

Get directions

Getting a campsite at William O Brien State Park

How do I get a campsite at William O Brien State Park when it's sold out?

Cancellations happen constantly — the trick is being first to know. Set an alert for your dates and we'll watch William O Brien State Park on Minnesota State Parks around the clock, then notify you the moment a site opens. Alerts run on a Pro subscription ($9.99/mo, cancel anytime).

When do campsites usually open up at William O Brien State Park?

Whenever someone cancels. Most reservation systems refund less the closer you get to arrival, so cancellations cluster in the days before a stay — but the openings themselves are unpredictable, which is exactly why watching for them beats refreshing the page.

Where do I book a campsite at William O Brien State Park?

Reservations for William O Brien State Park are made on Minnesota State Parks, the official booking system for Minnesota State Parks. GetParkAlerts is independent — we tell you when a site opens; you book it directly on the official site.

Parks near William O Brien State Park

Flexible on where you camp? Watch a few of these too — more parks, better odds.

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